JP6609614B2 - Preparation of bromine-containing polymers and their application as flame retardants - Google Patents

Description

  The present invention provides new high molecular weight polymers having pendent pentabromobenzyl groups suitable for use as flame retardants in flammable materials (eg, polyamides, polypropylene, and acrylonitrile-butadiene-styrene composites). .

  Brominated compounds are known to be very effective as flame retardants and often consist solely of materials that can reduce the combustion risk of synthetic materials. What needs to be developed now is a polymeric high molecular weight brominated flame retardant. It is hypothesized that the higher the molecular weight of the brominated flame retardant, the lower the volatility and the lower the potential for bioconcentration in living tissue.

Low molecular weight compounds containing pentabromobenzyl residues are known in the art. Pentabromobenzyl acrylate (EP 481126), pentabromobenzyl terephthalate (DE 33 20 333), and pentabromobenzyl tetrabromophthalate (EP 47866) are reported to be useful as flame retardant polymer compounds. Furthermore, poly (pentabromobenzyl acrylate) has been used as a flame retardant in flammable materials. Hereinafter, the pentabromobenzyl group may be represented by the following molecular structure or molecular formula —CH ₂ C ₆ Br ₅ :

  In the simultaneously assigned international patent application PCT / IL2014 / 000002 (≡WO 2014/106841) Friedel- of low molecular weight aromatic compounds such as alkyl-substituted benzenes (for example toluene, xylene, ethylbenzene) and diphenylalkanes The use of pentabromobenzyl halide as an alkylating agent in a crafts alkylation reaction has been described.

We, -CH ₂ C ₆ Br ₅ groups, electrophilic aromatic C- alkylation - incorporated in the aromatic ring-containing polymer via a synthetic route based on (Friedel also known as Crafts alkylation) It has been found that bromine rich polymers can be produced that can be used as flame retardants. Therefore, the present invention includes 6-membered aromatic rings in the form of side chains (as in polystyrene) or as part of the main chain (as in poly (phenylethyl)), and the pendent CH ₂ C ₆ Br ₅ group is , Wherein at least a part of the 6-membered aromatic ring of the polymer has a carbocyclic atom bonded to the aliphatic (benzylic) carbon of the CH ₂ C ₆ Br ₅ pendent group. A polymer to be attached is provided. The pentabromobenzyl group-containing polymer of the present invention has a high molecular weight, preferably 1,800 or more, such as 3,500 or more (eg,> 6,000), and its bromine content is preferably 60% or more, insoluble in water, and very stable to hydrolysis and / or alteration.

It should be noted that the present invention also relates to copolymers having two or more different types of repeat units, of course, at least one of the repeat units is fragrance of the at least one repeat unit via the benzylic carbon. Provided are those comprising an aromatic ring having a CH ₂ C ₆ Br ₅ pendent group attached to a ring carbon atom.

The polymers of the present invention can be divided into two broad categories, as illustrated in more detail in Formulas I and II, respectively: (I) Aromatic ring (containing a —CH ₂ C ₆ Br ₅ residue) And (II) a polymer in which an aromatic ring (including a —CH ₂ C ₆ Br ₅ residue) constitutes a part of the polymer main chain.

In the polymer of formula I, the benzene ring containing the —CH ₂ C ₆ Br ₅ group constitutes a side chain; R is Br or a linear or branched aliphatic chain, and k is 0-4. a separate integer, preferably 0 or 1, y is an integer, a = no of 1~ (5-k), ethylene _-CH 2 CH ₂ -, butylene _{-CH 2} CH = CHCH 2 -, Propylene-CH (CH ₃ ) CH ₂ —, isoprene-CH ₂ —CH═C (CH ₃ ) CH ₂ , and n and m are the number of units in the polymer chain (eg, in formula I, 3 ≦ n ≦ 1000 and m = 0, or 0.1n ≦ m ≦ 0.8n; in Formula II, 3 ≦ n ≦ 1000).

In the polymer of formula II, the benzene ring containing the —CH ₂ C ₆ Br ₅ group constitutes part of the main chain; X = none, O, S, CH ₂ , CH ₂ CH ₂ , and n are heavy The number of units in the combined chain.

Standard notation - [- B -] - representation of the polymer of the present invention by n is noted that it is not meant to include each and any unit may pendent -CH ₂ C ₆ Br ₅ groups of the polymer Should.

The polymer compound of the present invention is pentabromobenzyl halide, particularly pentabromobenzyl bromide (chemical name is 1- (bromomethyl) -2,3,4,5,6-pentabromobenzene, where (Abbreviated as PBBBr) as a polymer starting material containing at least one 6-membered aromatic ring as a repeating unit, and AlCl ₃ , AlBr ₃ , GaCl ₃ , FeCl ₃ , SnCl ₄ , SbCl ₃ , ZnCl _{2 as described above.} , CuCl ₂ , and HF or mixtures thereof are prepared by reacting in the presence of a suitable Friedel-Crafts catalyst (Lewis acid). It is preferred to use AlCl ₃ , alone or in combination with one or more other catalysts, in particular SnCl ₄ . For example, a mixture of AlCl ₃ and SnCl _{4 in} a molar ratio of 1: _{3 to 3} : 1, for example approximately 1: 1, could be successfully used to catalyze the reaction.

Accordingly, another aspect of the present invention is to repeat one or more 6-membered aromatic rings of pentabromobenzyl halide (HalCH ₂ C ₆ Br ₅ , where Hal represents a halide such as chloride or bromide). A method for preparing a bromine-containing polymer comprising a Friedel-Crafts alkalizing reaction with a polymer reactant contained in a unit, wherein the reaction occurs in a solvent at least in the presence of a Friedel-Crafts catalyst. . The products thus formed (formulas I and II) are characterized by the presence of a bond between the aromatic carbon ring atom of the polymer and the benzylic carbon of the pentabromobenzyl group.

Pentabromobenzyl bromide starting materials are commercially available (eg from ICL-IP) or by methods known in the art (eg US 6,028,156 and US 7,601,774). According to a synthetic route that can be prepared and includes aromatic bromination of toluene, a Lewis acid such as AlCl ₃ can be used, for example, in a halogenated solvent, using elemental bromine, as shown in the following scheme: In the presence of a catalyst, pentabromotoluene (hereinafter abbreviated as 5-BT) is formed, which is brominated with benzylic carbon using elemental bromine and a radical source such as azobisisobutyronitrile. The

A starting material that undergoes an aromatic substitution reaction, ie an electrophilic aromatic C-alkylation according to the present invention, has an aromatic ring in its repeating unit (or at least one repeating unit in the case of a copolymer starting material). It is a polymer containing. Preferably, the polymer starting material is represented by formula III or IV.

In formula III, R is a linear or branched aliphatic chain or bromine, k is an independent integer from 0 to 4, preferably 0 or 1, and A = none, ethylene-CH ₂ CH ₂ -, butylene _{-CH 2} CH = CHCH 2 -, propylene -CH _(CH 3) CH ₂ - or isoprene _{-CH 2 -CH = C (CH 3} ) CH 2, n and m are repeating in the polymer chain, The number of units.

In Formula IV, X = none, O, S, CH ₂ , CH ₂ CH ₂ , and n are the number of repeating units in the polymer chain.

Typical starting materials of formula III include:
polystyrene with k = 0, A = none, and m = 0;
k = 0, poly (styrene-co-ethylene) where A is —CH ₂ CH ₂ —; k = 0, A is poly (styrene-co-butadiene) where —CH ₂ CH═CHCH ₂ —; k = 0, A is a styrene copolymer (CAS250038-32-8) such as poly (styrene-co-isoprene) in which —CH ₂ —CH═C (CH ₃ ) CH ₂ .

  A typical starting material of formula IV includes poly (phenylethyl) and X = 0.

The Friedel-Crafts alkylation reaction according to the invention can be carried out in a single solvent or mixture of solvents, for example preferably from the group consisting of dichloromethane (DCM), dibromomethane (DBM), bromochloromethane and dichloroethane (DCE). Occurs in selected halogenated aliphatic hydrocarbons. The molar ratio of polymer starting material to HalCH ₂ C ₆ Br ₅ is appropriately adjusted to meet the desired degree of substitution in the aromatic ring of the polymer starting material. Generally, it is required to attach one or more —CH ₂ C ₆ Br ₅ groups to each 6-membered aromatic ring present in the polymer starting material. The amount of catalyst, eg AlCl ₃ or mixture of catalysts, is preferably in the range of 0.5% wt / wt to 2% wt / wt relative to HalCH ₂ C ₆ Br ₅ (eg amount of PBBBr). .

A reaction vessel is charged with solvent, polymer starting material (eg, polystyrene), HalCH ₂ C ₆ Br ₅ (eg, PBBBr) and catalyst. The reaction is dissolved upon heating, after which the catalyst is added. The polymer starting material and HalCH ₂ C ₆ Br ₅ are added to the reaction mixture simultaneously or sequentially. For example, when the polymer starting material is first dissolved in a solvent and becomes a clear solution, HalCH ₂ C ₆ Br ₅ (eg, PBBBr) is added to the solution, or the polymer solution is added to the HalCH ₂ C ₆ Br ₅ May be more convenient. The reaction is completed at a temperature of 40 ° C. or higher, for example, 40 ° C. to 90 ° C., more preferably 60 ° C. to 90 ° C. In general, the reaction time is 2 to 8 hours. The Friedel-Crafts alkylation reaction involves the generation of hydrogen bromide. The end of the reaction is indicated by either the complete consumption of PBBBr (determination is determined by gas chromatography analysis) or the cessation of odor hydrogen evolution.

  The product is separated from the reaction mixture using conventional techniques. The reaction mixture is washed repeatedly with water, aqueous sodium hydrogen sulfite (SBS) or alkaline solution (eg, sodium carbonate or sodium hydrogen carbonate), thereby destroying excess catalyst. When the polymer product does not spontaneously precipitate from the halogenated fatty acid hydrocarbon reaction solvent, precipitation is caused by combining the reaction mixture with a non-solvent, ie, a solvent in which the product does not inherently dissolve. Polar solvents such as acetone and lower alcohols such as isopropanol are well miscible with halogenated fatty acid hydrocarbons, but are useful as non-solvents. Upon cooling, the polymer product precipitates from a mixture of halogenated aliphatic hydrocarbon and acetone or isopropanol. The polymer product is recovered by filtration, optionally washed and dried.

The present invention relates to pentabromobenzyl halide HalCH ₂ as an alkylating reagent in Friedel-Crafts alkylation of polymers having aromatic ring-containing repeat units, for example polymers having aromatic ring-containing repeat units specified by formulas III and IV. It also relates to the use of C ₆ Br ₅ (eg PBBBr). Preferred polymer starting materials are polystyrene grades with a weight average molecular weight of 170,000-350,000 and polyphenylethyl grades with a weight average molecular weight of 400-350,000.

In a preferred embodiment, the present invention relates to a polymer starting material selected from the group consisting of a solvent (eg, halogenated fatty acid hydrocarbon), polystyrene and poly (phenylethyl), pentabromobenzyl halide HalCH ₂ C in a reaction vessel. ₆ Br ₅ (eg, PBBBr), one or more catalysts used for Friedel-Crafts alkalinization, a step of completing Friedel-Crafts alkalinization, and a bromine-containing polymer product, ie, pendent CH _And a step of recovering one having ₂ C ₆ Br ₅ groups. Preferably, the number of moles of HalCH ₂ C ₆ Br ₅ used in the reaction is greater than the total number of moles of aromatic rings in the polymer starting material. For example, if a polystyrene grade with a weight average molecular weight of approximately 200,000 is used, the average number of repeat units in the polymer chain is approximately 2000 (assuming the polystyrene repeat unit molecular weight is approximately 100). Therefore, 1 mol or more of HalCH ₂ C ₆ Br ₅ is used for 0.0005 mol of polystyrene starting material.

Preferred bromine-containing polymers of the invention are represented by Formula V where K = 0, m = 0, and y = 1 in Formula I.

  The pentabromobenzyl-substituted polystyrene provided by the present invention is characterized by having a bromine content of 60 wt% or more, for example, 60 to 70 wt%. The thermal stability profile of the preferred pentabromobenzyl substituted polystyrene of the present invention, typically expressed as thermogravimetric analysis (TGA), which measures the weight loss of the sample as the sample temperature is raised, is as follows: .

Another preferred bromine-containing polymer of the present invention is a polymer of formula II where X = 0 and y = 2 and is represented by formula VI.

  The pentabromobenzyl-substituted polyphenylethylene provided in the present invention is characterized by having a bromine content of 70 wt% or more, for example, 70 to 75 wt%. The thermal stability profile of preferred pentabromobenzyl substituted polyphenylethylenes of the present invention is typically as follows:

  A particularly preferred bromine-containing polymer of the present invention has a bromine content of 65 to 70 wt%, and a temperature of 370 ° C. or 370 ° C. or higher (preferably> 375 ° C. when TGA has a temperature rising rate of 10 ° C./min. ) And / or 10% weight loss at temperatures above 380 ° C. (preferably> 385 ° C.). The bromine content of the product is measured by a pearl cylinder method that involves bromination of the bromine-containing organic compound to obtain bromide and silver titration, as described in detail later. The experimental results reported below demonstrate that the addition of pentabromobenzyl substituted polystyrene reduces the flammability of the plastic material.

Bromine-containing polymers produced by Friedel-Crafts alkylation can be brominated (eg, with elemental bromine) to incorporate additional bromine atoms into the polymers of the present invention. One particular embodiment of the present invention comprises the step of preparing a bromine-containing polymer, which comprises (i) a polymer reactant having one or more 6-membered aromatic rings in a repeating unit and a pentabromobenzyl halide. A Friedel-Crafts alkylation reaction, wherein the reaction occurs in a solvent in the presence of at least one Friedel-Crafts catalyst to obtain a pentabromobenzyl substituted polymer, and (ii) Subjecting the formed pentabromobenzyl substituted polymer to a bromination reaction.

Bromination reactions also occur in halocarbons or mixtures of halocarbons, such as those used in alkylation reactions. A reaction vessel is charged with a solvent and a pentabromobenzyl-substituted polymer (eg, pentabromobenzyl-substituted polystyrene). Elemental bromine and a suitable catalyst (eg, a mixture with one or more leus acid catalysts as described above, particularly AlCl ₃ and other catalysts) are placed in a reaction vessel. Elemental bromine is slowly added to the reaction vessel in sufficient quantity to achieve the required degree of bromination, for example 1 or 2 bromine atoms per aromatic ring in the polymer. Completion of the bromination reaction is manifested by cessation of HBr production. The product is recovered by conventional methods. This method has a benzene ring having a —CH ₂ C ₆ Br ₅ group and a bromine atom (that is, R is Br and k = 1 or 2), and the bromine content is 70% or more (70 to 75 wt%) of bromine-containing polymers of formula I can be produced.

  Therefore, the bromine-rich polymer of the present invention is useful as a flame retardant in combustible materials. Accordingly, another aspect of the present invention is a flame retardant composition comprising a flammable material and the novel polymer of the present invention. For example, the bromine-containing polymers of the present invention can be used to reduce the flammability of polyamides, polypropylene and acrylonitrile-butadiene-styrene (ABS).

  The flame retardant composition of the present invention comprises an effective flame retardant amount of the novel bromine-containing polymer of the present invention, such as compounds of formulas I and II, and more preferably compounds of V and VI. Including. The concentration of the bromine-containing polymer of the present invention in the plastic formulation is such that the bromine content is at least 5 wt%, more preferably at least 10 wt%, such as 10-25 wt%, more preferably 10-20 wt% (a flame retardant plastic formulation). To the total weight of).

  Other conventional additives may also be included in the formulation. For example, an inorganic compound (typically a metal oxide) that can cooperate with a novel bromine-containing polymer is also preferably incorporated into the formulation. A preferred example of a suitable inorganic compound is antimony trioxide, which is commonly considered as an “inorganic synergist”.

  In particular, the novel bromine-containing polymer of the present invention exhibits excellent activity in polyamides. The polyamide-based composition of the present invention includes at least 30%, for example, 40 wt% to 70 wt% polyamide. The polyamide formulation further includes a reinforcing filler, i.e., glass fiber, which is typically in a manner known in the art prior to use to improve compatibility with the polyamide matrix. Covered. Such a modified form of glass fiber is available on the market as, for example, GF Chop Vantage 3660 from PPG. Glass fibers include filaments having a diameter in the range of 2 μm to 20 μm and are applied in the form of debris having a length in the range of 2 to 10 mm, for example 3 to 4.5 mm. For example, the main component of glass fiber applied to reinforced polyamide is aluminoborosilicate. Such kind of glass is known as E-glass. The glass fiber content is 5% to 40% of the total weight of the polyamide composition.

  In addition to polyamides, reinforcing fillers, bromine-containing polymers (eg, compounds of formula I or II), and antimony trioxide, the polyamide formulations of the present invention can further comprise lubricants, antioxidants (eg, hindered phenols). Or phosphite type), pigments, UV stabilizers and heat stabilizers. The content of each conventional additive listed above is typically in the range of 0.05 to 10 wt%.

  The polyamide composition is produced by melt-mixing the composition, for example, in a kneader or twin screw extruder, with a mixing temperature in the range of 200-300 ° C. For example, polyamide, bromine-containing flame retardant, and conventional additives (except for glass fibers) are dry mixed and the mixture is placed in the throat of the extruder. Glass fibers are added last, ie downstream.

Preferred polyamide compositions of the present invention include 100 parts by weight polyamide (eg, polyamide 6,6), 40-70 parts by weight glass fiber, 5-50 parts by weight pentabromobenzyl substituted polystyrene of formula V, and 3 Contains 15 parts by weight of inorganic synergist (eg, Sb ₂ O ₃ ).

  The novel bromine-containing polymer of the present invention also exhibits excellent activity in reducing the flammability of polypropylene. The polypropylene composition of the present invention comprises a polypropylene copolymer of 50 wt% or more (relative to the total weight of the composition), for example, 50 to 85 wt%, more preferably 50 to 70 wt%. Suitable polypropylene impact copolymers that can be used in the present invention include a first block (or phase) that is essentially a polypropylene homopolymer component and a second block (or phase) that is an ethylene-propylene copolymer component. ) In the form of a block copolymer. Polypropylene impact copolymers are produced by sequential polymerization reactions under conditions known in the art. In the first reaction, a homopolymer component is produced, and in the second reaction, a copolymer component is produced. Thus, the copolymer component is chemically incorporated into the matrix of homopolymer components. Various grades of polypropylene impact copolymers in the form of block copolymers are commercially available (trade names Capilene® SE50E, TR50, and SL50, Carmel Olefins, Israel). Impact modified polypropylene can be prepared by mixing polypropylene homopolymer and rubber. The compounds of the present invention can be used to reduce the flammability of polypropylene-based formulations without or containing fillers.

A preferred polypropylene composition of the present invention comprises 100 parts by weight polypropylene copolymer, 5-50 parts by weight pentabromobenzyl substituted polystyrene of formula V, and 2-20 parts by weight inorganic synergist (eg, Sb ₂ O ₃ )including. The filler-containing polypropylene further comprises 5 to 25 parts by weight of talc added in the form of powder or masterbatch pellets.

  The ABS composition of the present invention preferably comprises 50 wt% or more of ABS, for example 50 to 85 wt% ABS (relative to the total weight of the formulation). In the specification of the present invention, the term ABS refers to copolymers and terpolymers containing structural units corresponding to (optionally substituted) styrene, acrylonitrile and butadiene, regardless of the composition and production method. The characteristics and composition of ABS are described, for example, in Encyclopedia of Polymer Science and Engineering, Volume 16, pages 72-74 (1985). ABS with MFI (measured by ISO 1133 at 220 ° C./10 kg) in the range of 1-50 g / 10 min was used.

  The ABS formulation of the present invention is also preferably one or more anti-drip agents such as polytetrafluoroethylene (abbreviated as PTFE), preferably in the range of 0.025 to 0.4 wt%, more preferably 0.025 to It is contained in the range of 0.3 wt%, more preferably in the range of 0.05 to 0.2 wt%. PTFE is described, for example, in US Pat. No. 6,503,988.

  The plastic blends described above are readily prepared by methods known in the art. The various ingredients of the formulation are mixed together in their respective amounts. The material is first dry mixed using a suitable mixer such as a Henschel mixer. The resulting mixture is formed into homogeneous pellets using, for example, a twin screw extruder. The resulting pellets are dried and become suitable for molding processes such as injection molding. Other mixing and molding techniques can also be applied. Articles molded from polymer blends are another aspect of the present invention.

Example
Method
TGA analysis was performed using a Mettler-toledo instrument model 850. A 10 mg sample was heated in an aluminum oxide crucible from 35 ° C. to approximately 700 ° C. in a nitrogen atmosphere at a temperature increase rate of 10 ° C./min.

The bromine content in the compound was measured by the pearl cylinder method. A sample (˜0.08 to 0.12 g) was placed in a peroxide cylinder. Sucrose (0.5 g) was added, and a portion of sodium peroxide was also added. The sample was oxidized with sodium peroxide with a burner flame hitting the bottom of the cylinder. The burner was turned off when the bomb was heated to approximately 200 ° C. The bomb was placed in cold water (2 L). The gaseous product was absorbed with the alkaline mixture and kept in the bomb in the form of approximately sodium bromide. The contents of the bomb were mixed with warm water. Hydrazine sulfate was added to decompose the remaining sodium peroxide. Nitric acid was added until the solution was completely neutralized and acidic. The solution was cooled to room temperature and titrated with AgNO ₃ (0.1N) to determine the bromine content.

Example 1
Reaction of polystyrene with PBBBr using AlCl ₃ and SnCl ₄ DBM (1.8 L), and polystyrene with MW 170000-350,000 (104.15 g), mechanical stirrer, thermometer, condenser, HBr trap, and N ₂ inlet Into a 2 L reactor. The mixture was heated to 66 ° C. to make a clear solution. PBBBr (565.5 g) was dissolved in the solution. When AlCl ₃ (3.1 g) and SnCl ₄ (4.8 g) were added and the mixture was heated to 84 ° C., active HBr production began. The mixture was heated at 80 ° C. for 6 hours until PBBBr disappeared (by GC or HPLC). The reaction mixture was washed with water (1.5 L), saturated NaHCO ₃ solution (1.5 L) to pH = 7, and again three times with water (1.5 L), 30 minutes each wash. did. Thereafter, the reaction mixture was added dropwise to acetone (6 L) to cause precipitation. The reaction mixture was cooled to 20 ° C. and the solid was filtered and dried in an oven at 105 ° C. under reduced pressure for 12 hours to give 509 g, corresponding to a yield of 86% based on PBBBr. According to elemental analysis, the bromine content is approximately 68%, which corresponds approximately to one PBBBr molecule per aromatic ring. The TGA profile of this product is shown in the table below.

Example 2
Reaction of polystyrene with PBBBr using AlCl ₃ PBBBr (27.1 g), polystyrene (10.0 g), AlCl ₃ (0.2 g), and dichloroethane (100 mL) as the solvent, except that dichloroethane (100 mL) was used. The procedure was repeated. The weight of the product was 24.0 g, corresponding to a yield of ˜72% based on PBBBr. The bromine content was approximately 60.0%.

Example 3
Reaction of polyphenylethyl with PBBBr Polyphenylethyl [Santovac 7, available at Santolubes LLC, MW-450 (30 g)], PBBBr (366.4 g), and DBM (700 mL) were added to a mechanical stirrer, thermometer, condenser, Placed in 1 L reactor with HBr trap and N ₂ inlet. The mixture was heated to 70 ° C. and AlCl ₃ (3.5 g) was added in a proportion. The mixture was stirred at 90 ° C. until PBBBr disappeared (5-6 h). The reaction mixture was washed with water (250 mL) and SBS (2.5 mL, ˜28%), water (250 mL), 5% Na ₂ CO ₃ (250 mL), and water (250 mL) for 20 minutes each wash. And washed at 50 ° C. Solvent (˜150 mL) was evaporated under reduced pressure. The residue was heated to 40-50 ° C. and added dropwise to 50 ° C. IPA (450 mL) with vigorous stirring over 1 hour. The mixture was stirred at 50 ° C. for 1 hour and cooled to 18 ° C. The solid was filtered and washed on the filter with IPA (150 mL). The solid is oven dried at 105 ° C. and 150 ° C. under reduced pressure for 3 and 7 hours, respectively, to give a white powder product (318 g, corresponding to a yield of ˜92% based on PBBBr) It was. The bromine content was approximately 75.0%. The TGA profile of this product is shown in the table below.

Example 4
Bromination of the product of Example 1 DBM / DCM (1495 g / 96 g) and the product of Example 1 (191.3 g) were added to a mechanical stirrer, addition funnel, thermometer, condenser, HBr trap, and N ₂ inlet. Equipped with a 2 L reactor. The mixture was heated to 60 ° C. to make a clear solution. Br ₂ (38.2 g) was added dropwise to the solution over 0.5 h. AlCl ₃ (1.0 g) and SnCl ₄ (2.0 g) are added, the mixture is heated to 65 ° C., and additional Br ₂ (76.4 g) is added dropwise to produce vigorous HBr production. Was started. The mixture was heated at 65 ° C. for 6 hours until formation of HBr was observed (by titration). The reaction mixture was washed with water (1.0 L), saturated NaHCO ₃ solution (1.0 L), and again with water (1.0 L) for 30 minutes for each wash to pH = 7.

  The reaction mixture was then added dropwise to isopropanol (1.5 L), causing precipitation. The reaction mixture was cooled to 20 ° C., the solid was filtered and dried in an oven at 105 ° C. under reduced pressure for 12 hours to give 218 g, corresponding to a yield of ˜89%.

  According to the analysis, the bromine content is approximately 72%, which corresponds to approximately PBBBr2 molecules per aromatic ring. The TGA profile of this product is shown in the table below.

  The studies reported in the following examples evaluate the ability of the pentabromobenzyl substituted polystyrene of Example 1 to reduce flammability in various thermoplastics. Test pieces were prepared and subjected to the following tests.

Flammability test The flammability test was conducted according to the Underwriters-Laboratories standard UL94 for vertical combustion in 0.8 mm or 1.6 mm thick samples.

The mechanical property impact strength was measured using an Izod notch test according to ASTM D-256-81 using a pendulum impact tester 5102 (manufactured by Zwick).

  Tensile properties (tensile strength, tensile modulus, elongation at break) were measured with a Zwick 1435 physical property tester according to ASTM D-638-95 (v = 5 mm / min).

Other characteristics HDT (thermal deformation temperature; this is the temperature at which the polymer sample deforms at a specific load) was measured according to ASTM D-648-72 at a load of 1820 kPa and a heating rate of 120 ° C./h. HDT / Vicat-plus (Davenport, Lloyd instruments) was used as the apparatus.

  MFI (Melt Flow Index) was measured by ASTM D1238 (230 ° C / 2.16kg for PP, 250 ° C / 1.2kg for polyamide). Meltfixer 2000 (Thermo Hake) was used as the apparatus.

Example 5 (comparative example) and Example 6 (present invention)
V-0 Standard Polyamide 6,6 Formulation In this example, the pentabromobenzyl substituted polystyrene of Example 1 was tested to evaluate the ability of polyamide 6,6 to reduce flammability. In the comparative example, the corresponding formulation was similarly prepared, but the flame retardant was another bromine-containing polymer (FR-803P; polystyrene bromide, commercially available from IC-IP).

The materials used in the material experiments used for the preparation of the composition are shown in Table 1 (FR is an abbreviation for flame retardant).

Polyamide composition and test sample preparation materials were mixed in a twin screw co-rotating extruder (Berstorff ZE25) with L / D = 32. Polyamide, bromine-containing flame retardant and all other additives—except glass fiber—weighed and mixed and the resulting mixture was fed to the main feed port of the extruder. Glass fibers were placed in the fifth section of the extruder by side feeding. The temperature profile was 250-260-265-265-265-270-275-280 ° C. The screw speed was 350 rpm and the feed speed was 12 kg per hour.

  The resulting extrudate was pelletized in a pelletizer 750/3 (Acrapac Systems Limited). The resulting pellets were dried in an air circulating oven at 120 ° C. for 4 hours and overnight in a vacuum oven at 80 ° C.

  The dried pellets were injection molded into test samples using Allrounder 500-150 (Arburg). Table 2 shows the injection molding conditions.

  The manufactured sample was allowed to stand at 23 ° C. for one week to prepare the conditions, and a series of tests were performed. The compositions produced and the results of the tests are shown in Table 3.

  From the results shown in Table 3, it can be seen that pentabromobenzyl-substituted polystyrene and commercially available brominated polystyrene show similar excellent results as flame retardants in polyamides. The flammability and mechanical properties of the exemplified polyamide blends were comparable.

Examples 7-8 (comparative examples) and Example 9 (present invention)
V-0 rated talc-free polypropylene formulation The pentabromobenzyl-substituted polystyrene of Example 1 was tested to evaluate the ability of the polypropylene copolymer (no talc) to reduce flammability. In the comparative example, two corresponding formulations were prepared, but decabromodiphenylethane and poly (pentabromobenzyl acrylate) as flame retardants (FR-1410 and FR-1025, respectively, both commercially available from ICL-IP Possible). The materials used to prepare the composition are shown in Table 4.

Preparation mixing of the polypropylene composition and the test sample was performed in a twin screw co-rotating extruder ZE25 at L / D = 32. The temperature profile was 120-180-200-200-200-210-220-230 ° C. The screw speed was 350 rpm and the feed speed was 12 kg per hour.

  The resulting extrudate was pelletized in a pelletizer 750/3 (Accrapac Systems Ltd). The obtained pellets were dried in an air circulating oven at 80 ° C. for 3 hours. The dried pellets were injection molded into test samples (thickness 1.6 mm) using Allrounder 500-150 (Arburg). Table 5 shows the injection molding conditions.

  The sample was allowed to stand at 23 ° C. for one week to prepare the conditions, and a series of tests were performed. The results are shown in Table 7.

  The results show that pentabromobenzyl substituted polystyrene was added to the polypropylene copolymer at a lower content compared to other bromine containing flame retardants and passed the UL-94V-0 flammability test. The pentabromobenzyl substituted polystyrene of the present invention can achieve a UL-94V-0 rating, with the help of 9.5 wt% antimony trioxide in a 19 wt% bromine polypropylene copolymer. . The comparative brominated flame retardant tested requires the addition of more bromine and antimony trioxide to give a UL-94V-0 rating to the polypropylene copolymer.

Examples 10-12 (present invention)
V-1 Evaluation Talc-Containing Polypropylene Formulation The purpose of these examples is to evaluate the ability of the pentabromobenzyl-substituted polystyrene of Example 1 to reduce the flammability of talc-containing polypropylene formulations.

Materials used for preparing the composition Table 8 shows the materials used for preparing the polypropylene composition.

The polypropylene composition and test sample preparation materials were mixed in a twin screw co-rotating extruder (Berstorff ZE25) with L / D = 32. The temperature profile was 120-180-200-200-200-210-220-230 ° C. The screw speed was 350 rpm and the feed speed was 12 kg per hour.

  The resulting extrudate was pelletized in a pelletizer 750/3 (Accrapac Systems Ltd). The obtained pellets were dried in an air circulating oven at 80 ° C. for 3 hours.

  The dried pellets were injection molded into test samples using Allrounder 500-150 (Arburg) according to the parameters in Table 9.

  The sample was allowed to stand at 23 ° C. for 1 week for adjusting the conditions and tested. The compositions and results are shown in Table 10.

Claims (19)

A Friedel-Crafts alkylation reaction of a pentabromobenzyl halide with a polymer reactant having one or more 6-membered aromatic rings in the repeating unit;
A process for preparing a bromine-containing polymer, wherein the reaction proceeds in a solvent in the presence of at least one Friedel-Crafts catalyst.   The process according to claim 1, wherein the pentabromobenzyl halide is pentabromobenzyl bromide. The process according to claim 1 or 2, wherein the polymer starting material is represented by formula III or formula IV.

In formula III, R is an aliphatic chain or bromine straight or branched chain; k are independently integers of 0 to 4; A is _{no, -CH 2 CH 2 -, -} CH 2 CH = _{CHCH 2 -, - CH (CH} 3) CH 2 -, and _{-CH 2 -CH = C (CH 3} ) is selected from the group consisting of CH _2; n and m is the number of repeating units in the polymer chain;
In Formula IV, X is selected from the group consisting of none, O, S, —CH ₂ — and —CH ₂ CH ₂ —, and n is the number of repeating units in the polymer chain.   The polymer starting material is either a polymer of formula III where k = 0, A = none, m = 0 (polystyrene), or a polymer of formula IV where X = 0 (poly (phenylethyl)). Item 4. The method according to Item 3. The solvent in the reaction vessel, polystyrene as the polymer starting material, pentabromobenzyl halide and Friedel - step add 1 or more of the catalyst used in Crafts alkylation, Friedel - step to fully achieve Crafts alkylation, and pendent - The method of claim 4, comprising recovering bromine-containing polystyrene having CH ₂ C ₆ Br ₅ groups. AlCl ₃ and catalyzes the reaction using a mixture of SnCl _4, The method according to claim 1. Furthermore, the method in any one of Claims 1-6 including the process of carrying out the bromination reaction of the polymer which has the pendent pentabromo benzyl group formed in that way. A <br/> polymer having a repeating unit containing a 6-membered aromatic ring, pendent -CH ₂ C ₆ Br ₅ groups are attached to at least a portion of the 6-membered aromatic ring of the polymer, the 6 A polymer in which a carbon ring atom of a member aromatic ring is bonded to an aliphatic carbon of the —CH ₂ C ₆ Br ₅ pendent group, and the polymer has 3 or more repeating units . Formula I or II:

Represented by
In formula I:
R is Br or a linear or branched aliphatic chain;
k is an independent integer from 0 to 4;
y is an integer from 1 to (5-k);
A is _{no, -CH 2 CH 2 -, -} CH 2 CH = CHCH 2 -, - CH (CH 3) CH 2 -, and selected from _{-CH 2 -CH = C (CH 3} ) group consisting of CH ₂ Is;
n and m are the number of units in the polymer chain, n ≧ 3,
In Formula II:
X is selected from the group consisting of none, O, S, CH ₂ , and —CH ₂ CH ₂ —;
n is Ri number der the number of units in the polymer chain, n ≧ 3,
The polymer according to claim 8.   10. The polymer of claim 9, wherein the polymer of formula I is a pentabromobenzyl substituted polystyrene.   10. A polymer according to claim 9, wherein the polymer of formula II is pentabromobenzyl substituted poly (phenylethyl).   The polymer of Claim 10 whose bromine content is 60 wt% or more. The polymer of Claim 11 whose bromine content is 70 wt% or more. Use of a pentabromobenzyl halide of formula HalCH ₂ C ₆ Br _{5 comprising} :
Hal is bromide or chloride and is used as an alkylating reagent in Friedel-Crafts alkylation of polymers having aromatic ring-containing repeat units.   A flame retardant composition comprising a combustible material and a bromine-containing polymer according to any one of claims 8 to 13.   The flame retardant composition according to claim 15, wherein the bromine-containing polymer is the pentabromobenzyl-substituted polystyrene according to claim 12.   The flame retardant composition according to claim 15 or 16, wherein the combustible polymer is polyamide.   The flame retardant composition according to claim 15 or 16, wherein the combustible polymer is a polypropylene copolymer or impact-modified polypropylene.   19. The flame retardant composition of claim 18, comprising 100 parts by weight polypropylene copolymer, 5-50 parts by weight pentabromobenzyl substituted polystyrene, and 2-20 parts by weight antimony trioxide.